package wang.miansen.roothub.common.util;

import java.io.UnsupportedEncodingException;
import java.util.Base64;
import java.util.Base64.Decoder;
import java.util.Base64.Encoder;

public class Base64Util {

	private Base64Util() {}

	/**
	 * base64编码
	 * @param str
	 * @return
	 */
	public static String encode(String str) {
		byte[] encode = null;
		String string = null;
		try {
			Encoder encoder = Base64.getEncoder();
			if(str != null) encode = encoder.encode(str.getBytes("utf-8"));
			if(encode != null) string = new String(encode, "utf-8");
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
		return string;
	}
	
	/**
	 * base64解码
	 * @param str
	 * @return
	 */
	public static String decode(String str) {
		String string = null;
		byte[] decode = null;
		try {
			Decoder decoder = Base64.getDecoder();
			if(str != null) decode = decoder.decode(str);
			if(decode != null) string = new String(decode, "utf-8");
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
		return string;
	}
	
	/*public static void main(String[] args) {
		String str = "一颗协议";
		String encode = encode(str);
		System.out.println(encode);
		String decode = decode("5LiA6aKX5Y2P6K6u");
		System.out.println(decode);
	}*/
	private static char[] base64EncodeChars = new char[]{'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
		      'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c',
		      'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
		      'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'};
		  private static byte[] base64DecodeChars = new byte[]{-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
		      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
		      -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1,
		      -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,
		      22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
		      40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1};

		  /**
		   * 加密
		   *
		   * @param data
		   * @return
		   */
		  public static String encode(byte[] data) {
		    StringBuffer sb = new StringBuffer();
		    int len = data.length;
		    int i = 0;
		    int b1, b2, b3;
		    while (i < len) {
		      b1 = data[i++] & 0xff;
		      if (i == len) {
		        sb.append(base64EncodeChars[b1 >>> 2]);
		        sb.append(base64EncodeChars[(b1 & 0x3) << 4]);
		        sb.append("==");
		        break;
		      }
		      b2 = data[i++] & 0xff;
		      if (i == len) {
		        sb.append(base64EncodeChars[b1 >>> 2]);
		        sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);
		        sb.append(base64EncodeChars[(b2 & 0x0f) << 2]);
		        sb.append("=");
		        break;
		      }
		      b3 = data[i++] & 0xff;
		      sb.append(base64EncodeChars[b1 >>> 2]);
		      sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);
		      sb.append(base64EncodeChars[((b2 & 0x0f) << 2) | ((b3 & 0xc0) >>> 6)]);
		      sb.append(base64EncodeChars[b3 & 0x3f]);
		    }
		    return sb.toString();
		  }

		  /**
		   * 解密
		   *
		   * @param str
		   * @return
		   */
		  public static byte[] decode2(String str) {
		    try {
		      return decodePrivate(str);
		    } catch (UnsupportedEncodingException e) {
		      e.printStackTrace();
		    }
		    return new byte[]{};
		  }

		  public static boolean isBase64(String str) {
		    try {
		      decode(str);
		      return true;
		    } catch (Exception e) {
		      return false;
		    }
		  }

		  private static byte[] decodePrivate(String str) throws UnsupportedEncodingException {
		    StringBuffer sb = new StringBuffer();
		    byte[] data = null;
		    data = str.getBytes("US-ASCII");
		    int len = data.length;
		    int i = 0;
		    int b1, b2, b3, b4;
		    while (i < len) {

		      do {
		        b1 = base64DecodeChars[data[i++]];
		      } while (i < len && b1 == -1);
		      if (b1 == -1)
		        break;

		      do {
		        b2 = base64DecodeChars[data[i++]];
		      } while (i < len && b2 == -1);
		      if (b2 == -1)
		        break;
		      sb.append((char) ((b1 << 2) | ((b2 & 0x30) >>> 4)));

		      do {
		        b3 = data[i++];
		        if (b3 == 61)
		          return sb.toString().getBytes("iso8859-1");
		        b3 = base64DecodeChars[b3];
		      } while (i < len && b3 == -1);
		      if (b3 == -1)
		        break;
		      sb.append((char) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));

		      do {
		        b4 = data[i++];
		        if (b4 == 61)
		          return sb.toString().getBytes("iso8859-1");
		        b4 = base64DecodeChars[b4];
		      } while (i < len && b4 == -1);
		      if (b4 == -1)
		        break;
		      sb.append((char) (((b3 & 0x03) << 6) | b4));
		    }
		    return sb.toString().getBytes("iso8859-1");
		  }
}
